Related Experiment Videos
Restriction of poliovirus RNA translation in a human monocytic cell line
J A López-Guerrero1, L Carrasco, F Martínez-Abarca
1Centro de Biología Molecular, Universidad Autónoma, Madrid, Spain.
Abstract:
The infection of the human monocytic cell line U-937 by poliovirus was characterized by a low level of virus production and a slow progression of the cytopathic effect. Infection took place in greater than 99% of the cells as revealed by a limiting dilution assay. No viral protein synthesis was evident in the infected U-937 cells when analyzed by polyacrylamide gel electrophoresis. However, a low level of poliovirus RNA translation was detected by immunofluorescence analysis using a mixture of polyclonal antisera against non-structural proteins. Although there was only a low level of viral protein synthesis, a gradual accumulation of viral mRNA took place in U-937 cells as revealed by RNA blot analysis. Similar results were obtained when the erythroleukemic cell line K-562 was used as a host cell for poliovirus. RNA extracted from infected U-937 cells was efficiently translated in rabbit reticulocyte extracts giving rise to a pattern of viral polypeptides similar to that detected when virion-purified RNA was the template used for the in vitro translation assay, suggesting that the poliovirus RNA present in infected U-937 cells is functional. The existence in U-937 cells of a discriminatory mechanism which differentially interferes with poliovirus RNA translation is discussed.
Insights
Poliovirus infection in U-937 cells shows limited viral protein synthesis despite functional viral RNA. This suggests a cellular mechanism specifically hindering poliovirus RNA translation in these cells.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Poliovirus typically causes rapid cell death and high viral production in susceptible cells.
- The human monocytic cell line U-937 is known to be permissive to some viral infections.
Purpose of the Study:
- To characterize the infection of U-937 cells by poliovirus.
- To investigate the mechanisms underlying viral replication and protein synthesis in this cell line.
Main Methods:
- Infection of U-937 and K-562 cell lines with poliovirus.
- Limiting dilution assays to determine infection efficiency.
- Polyacrylamide gel electrophoresis and immunofluorescence for viral protein analysis.
- RNA blot analysis for viral mRNA accumulation.
- In vitro translation assays using RNA from infected cells.
Main Results:
- Poliovirus infected >99% of U-937 cells but resulted in low virus production and slow cytopathic effects.
- No significant viral protein synthesis was detected in infected U-937 cells.
- Low-level viral RNA translation and gradual viral mRNA accumulation were observed.
- RNA from infected U-937 cells was functional in vitro, indicating intact viral RNA.
Conclusions:
- U-937 cells exhibit a unique cellular mechanism that selectively inhibits poliovirus RNA translation.
- Despite functional viral RNA, efficient protein synthesis is impaired, leading to restricted viral replication.
- This finding opens avenues for understanding host-pathogen interactions and potential antiviral strategies.